Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
2
4
2012
06
20
Evaluation of Error Due to Applying Average Rating Curve as downstream Boundary Condition in Unsteady Flow Modeling
7
18
EN
Mehdi
Habibzadeh
Department of Hydraulic Structures, Science and Research Branch, Islamic Azad
University, Khouzestan, Iran
mehdius3@gmail.com
H
Mohammad Vali Samani
Department of Hydraulic Structures, Science and Research Branch, Islamic Azad
University, Khouzestan, Iran
H
Kashkuli
Department of Hydraulic Structures, Science and Research Branch, Islamic Azad
University, Khouzestan, Iran
The rating curve is the relationship between the water stage and the associated discharge in a given<br />section of a channel. In steady flow, this relationship usually has exponential type, whereas in<br />unsteady it flow has a looped shape. Since direct developing of actual looped rating curve by using<br />hydrometric methods is merely possible, steady-state rating curve is commonly used as a downstream<br />boundary condition in mathematical modeling of unsteady flow which leads to relevant error in model<br />results. In this study, in order to evaluate this error, a method is presented by using the HEC-RAS<br />model of unsteady flow in a prismatic channel with different bed slopes, roughness coefficients and<br />channel lengths as effective parameters. In various channel geometries , the rating curves of both the<br />approximate and the reference states are obtained. Then statistical comparison between the results was<br />done. Accordingly, 120 R-squared (R2) values refer to 240 different channel conditions, were<br />considered and the errors were analyzed which indicate that the error is declined by increasing bed<br />slope and channel length, in addition by roughness reduction. The maximum rate of the error occurred<br />by any of effective parameters including bed slope, roughness coefficient and channel length was<br />evaluated in order of appearance; 0.2617, 0.1507 and 0.1673. In addition, the sensitivity of all the<br />parameters in different modeling conditions may be distinguished by using the obtained graphs.
Rating Curve,Unsteady Flow,Mathematical Modeling,Downstream Boundary Condition,HECRAS
http://wsej.iauahvaz.ac.ir/article_529649.html
http://wsej.iauahvaz.ac.ir/article_529649_37a716733b8caf747021744440e6073a.pdf
Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
2
4
2012
06
20
Investigation of the Effect Soil particles size on the Currency Time Domain Reflectometry for water content measurement
19
30
EN
E
Maroufpoor
Department of Water Engineering , University of Kurdistan, Iran.
isamarofpoor@yahoo.com
M
Behzadi Nasab
Regional Water Company of Kurdistan, Kurdistan, Iran.
This study carried out on the provided textures at laboratory. The provided textures were infused<br />inside the PVC cylinder with 30cm height and 25cm diameter. The studied textures were loamy<br />sand, sandy loam, sandy clay-loam, clay loam and clay. After 24 hours of saturation, the soil water<br />content of the samples was measured by oven-dry gravimetric and TDR methods. For each textures<br />at any stage of measurement the determination of moisture and di-electric constant were done at<br />three capture windows and with three repetitions. In each day the moisture measurement of each<br />texture was carried out by these two methods until a moisture range was determined. The results of<br />this research show that: 1- For all soil textures the measured moisture at the capture windows of 20<br />ns has more accuracy compared to the other capture windows. and TDR device can not measure the<br />soil water content at capture window of 40 ns. 2- For loamy-sand and sandy-loam textures when the<br />moisture was less than 20% and also for other textures for total range of measurement, the TDR<br />device measured the moisture values less than the gravimetric method. This difference is increased<br />when the soil ranged from light to heavy textures. 3- From the statistical view at probably level of<br />1% there is not difference between the measured value of moisture by TDR device and gravimetric<br />method. 4- For the all textures the fitted regression lines have high regression coefficient.
TDR,Calibration,Soil texture
http://wsej.iauahvaz.ac.ir/article_529650.html
http://wsej.iauahvaz.ac.ir/article_529650_c24a7dc1983ed8df77624164fe447aad.pdf
Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
2
4
2012
06
20
Studying the effect of sediment control structures of sill on sediment entrance into the intake with different angles
31
50
EN
A
Makvandi
Department of Hydraulic Structures, Dezfoul Branch, Islamic Azad university, Dezfoul, Iran .
aidamakvandi@gmail.com
A
Telvari
civil engineering department, Islamic azad university of Ahvaz, Iran.
M
Mashal
Department of Irrigation and Drainage Engineering, College of Aboureihan,
University of Tehran Pakdasht, Iran .
Using lateral intake is a method of floodwater diverting. In arid and semi-arid areas, floodwater<br />contains a large amount of sediment that will be carried in to the intakes and it causes a reduction in<br />channel conveyance. Sediment is almost transported into the intake and it is settled in the upstream<br />side of lateral channel. Sedimentation in this zone reduces the conveyance of lateral channel and it<br />blocks the entrance of intake. There are several methods to reduce sediment transport into the intake<br />that one of them is noticed to the angle of lateral channel related to the flow direction in the main<br />channel. Using the sediment control structures such as sill is the other approach. In the present study,<br />CCHE2D model is used to simulate the results of a laboratory study that has been conducted in the<br />past. The laboratory study has been experimented in a flume approximately 17 m in length, 1.5 m in<br />width and 7 m in depth. The intake connected to the flume has a width of 0.6 m, a length of 2.5 m with<br />different angles of 90, 75, 60 and 45 degrees to the flow main direction. The bed material was sand<br />with an average diameter of 1 mm that is casted in 20 cm thick on the bed of flume. The model<br />CCHE2D was applied once as a simple model and again a model with use of a sill with height of 3.5<br />cm and 1 cm thickness at the entrance of intake, Range of tests was so that there was just movement of<br />bed load. Presence of sill structure has been approximately decreased 26 percent of the sediment<br />entrance into the intake, whereas this figure for the tests was 30 percent. This indicates the ability of<br />CCHE2D model to predict the sill effect on sediment control.
Sediment control,Bed load,sill structure,Intake angle,CCHE2D
http://wsej.iauahvaz.ac.ir/article_529663.html
http://wsej.iauahvaz.ac.ir/article_529663_43b3ada750ee07eacaec15e20f0eeb4e.pdf
Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
2
4
2012
06
20
Economic impacts of climate variabity on water use and production of wheat in the khouzestan province
51
68
EN
N
Zohrabi
Science and Research Branch, Islamic Azad University, Khouzestan- Iran
nasreh.hemadi@gmail.com
N
Hemadi
Department of Agricultural Economics, Science and Research Branch, Islamic Azad University,
Khouzestan,Iran.
R
Moghadasi
Department of Agricultural Economics, Science and Research Branch, Islamic Azad University,
Tehran, Iran.
In this study a research, there was conducted on the change regarding the climatic parameters of<br />temperature and rainfall along with their sequential quantitative changes in the province Khouzestan.<br />Then the economic effect on water use and the net income of wheat, was assessed by applying<br />Ricardian method. The results of the statistical analysis using Mann-Kendall test proved the existence<br />of the trend for temperature in a given time span, with an incremental pattern. but In the time span for<br />rainfall, however , the trend showed a falling pattern in Ahvaz, rejecter the existence of such a trend<br />in Dezful, showing also a low falling pattern for Shadegan station .The increasing pattern of the need<br />for water as with wheat concerning the areas Dezful, Ahvaz and Shadegan were 2106, 2500, 3129<br />cubic meter in a century's time span, respectively the annual decrease in crop for wheat owing to<br />some climatic variations, too, for Dezful, Ahvaz and Shadegan were (as much as) 24587, 19291,<br />18360, respectively. More over, the results of Ricardian model of study predicated that the rise in<br />temperature and the fall in rainfall would cause about a reduction of 57863 thousand RLS. In the<br />wheat crop output each hectare in a century's time.
Climatic variations,Ricardian,Consumption water,Net income,Khouzestan
http://wsej.iauahvaz.ac.ir/article_529664.html
http://wsej.iauahvaz.ac.ir/article_529664_c6793f1ad2d365d8f613411446cc489b.pdf
Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
2
4
2012
06
20
The study of water enterainment of plung region in density currents
69
82
EN
D
Karami Cheme
Graduated of Watre Structures, Sari Agricultural Sciences and Natural Resources University
and Expert of Dezab Consalting Engineering , Iran.
kdariush44@yahoo.com
S.H.
golmaei
Associate of Sari Agricultural Sciences and Natural Resources University, Iran.
A
Shah Nazari
Associate of Sari Agricultural Sciences and Natural Resources University, Iran.
E
Hoseinian
Graduated of Water Structures, Faculty of Water Science, Shahid Chamran University
of Ahwaz, Iran.
The Study of river water quality interation with lakes and dam reservoirs is important from an<br />exploitation point of view. When river water with different densities enters a lake or dam reservoir,<br />underflow density current phenomenon occurs. Because of the density, so understanding<br />different arrays of this phenomenon Seems necessary for checking erosion and sedimentation<br />processes and their management in dams reservoir. one of the important arrays in density<br />current phenomena is the enterainment of ambient water caused by the underflow density current.<br />In this research, enterainment in plunging region for this flows studied by the physical model and<br />checking three parameters: entrance flow's Concentration, bed slop, and entrance discharge.<br />Experiments were performed in a flume With 9.75 m length, 50 cm in width and 80 cm height, three<br />slops and four concentration, with different discharges. The experimental results indicated that bed<br />slop had a direct influences on the enterainment rate of ambient water in the plunging region.
density current,Plunge region,Richardson number,Enterainment of ambient water,Physical model
http://wsej.iauahvaz.ac.ir/article_529665.html
http://wsej.iauahvaz.ac.ir/article_529665_b7489df66e3460ea1aa4668a75807e8e.pdf
Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
2
4
2012
06
20
Comparison of One-point and Two-point Methods for Estimation of Infiltration Parameters in Furrow Irrigation
83
96
EN
J
Jafari
MSc student, Department of Water Engineering, University of Tabriz, Iran
F
Taran
MSc student, Department of Water Engineering, University of Tabriz, Iran
farshidtaran@gmail.com
R
Dalir Hasan Nia
Assist. Prof, Department of Water Engineering, University of Tabriz,Iran.
A.H.
Nazemi
Department of Water Engineering, University of Tabriz,Iran.
Infiltration is one of the most important hydraulic parameters affecting surface irrigation and one of<br />the most difficult parameters in practical field determinations. The infiltration equations are used to<br />describe water flow hydraulics and surface irrigation systems design. But determination of the<br />parameters in these equations are costly and time consuming. Therefore, some estimating methods are<br />used for this purpose. In this study , three inflow-outflow (as the base method), Shepard et al.’s onepoint<br />method and Elliot and Walker two-point method were used to determine the parameters of the<br />infiltration equations. By comparing with the inflow-outflow method, the accuracy of the one point<br />and two point methods were evaluated for volumetric determination infiltrated water. For this purpose,<br />the collected data from 201C1 and 201E sugarcane farms in Haft-Tappeh with furrow irrigation<br />system were analyzed. The data were collected under different inflow rates and furrow lengths. The<br />results showed that the Elliot and Walker two-point method with relative errors of 8.08 percent for<br />201C1 farm and 12.85 percent for 201E farm had more accuracy in relation to the Shepard et al.’s onepoint<br />method with in estimation of cumulative infiltration depth. This method had also more<br />satisfactory results with relative errors of 4.03 percent and 6.41 percent for 201C1 and 201E farms,<br />respectively.
Furrow Irrigation,Infiltration parameters,Inflow-outflow method,One-point method,Two-point method
http://wsej.iauahvaz.ac.ir/article_529666.html
http://wsej.iauahvaz.ac.ir/article_529666_5808e719ea1f4342673a62cbfea39a05.pdf
Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
2
4
2012
06
20
Modeling of pollutant transmission in rivers By using Finite volume method and ANFIS model
97
118
EN
A
پارسائی
0000-0001-7312-0634
Hydro Structures, Water Engineering Department, University of Lorestan, Iran.
abbas_parsaie@yahoo.com
M.M
Ahmadi
Assistant Professor, Department of Water Engineering,Iran.
K
Ghaderi
Assistant Professor, Department of Water Engineering,Iran.
Study in surface water quality is important. Rivers are one of the main sources of water supply for<br />drinking, agriculture and industry. Unfortunately, sometime Rivers where wastewater discharges<br />are considered. For this reason,the pollutant transmission in river is one of the most important<br />problems in Environmental Engineering. the Advection Dispersion Equation (ADE) is governed<br />on the pollutant transport in river. this equation is partial differential equation (PDE). This<br />equation is used most widely in fluid engineering spatially water engineering and in general<br />named convection equation.to Preparate computer programs that can simulate the pollutant<br />transmission, in addition to the used numerical method to solution of the convection equation ,the<br />calculation of Longitudinal Dispersion coefficient (LDC) is needed. Many empirical formulas are<br />presented for calculating the LDC. the assessment of this equations shows that Most of their<br />accuracy is not satisfactory. Thus the use of Artificial Intelligent techniques is inevitable. In this<br />paper, the finite volume method is used discretiz of ADE and to estimate the diffusion coefficient,<br />adaptive neural network (ANFIS) has been developed. the result of ANFIS model shows that The<br />accuracy and performance of the model in training and testing process is very suitable. After the<br />development of an artificial intelligence model general model was developed. the result of the<br />final model tested with analytical solution of ADE and observation data of the Severn River in the<br />UK. the final result show that performance of model is suitable.<br />Keywords: transmission of pollutant, finite volume method, Severn river
transmission of pollutant,Finite volume method,Severn river,Numerical Method,ANFIS model
http://wsej.iauahvaz.ac.ir/article_529667.html
http://wsej.iauahvaz.ac.ir/article_529667_b0b142292aa69677e4dbc2eab8aafbd0.pdf